The dual pathway in action: decoupling parallel routes for CO2 production during the oscillatory electro-oxidation of methanol

Author(s)

Nagao, Raphael ^[1] ; Cantane, Daniel A. ^[1] ; Lima, Fabio H. B. ^[1] ; Varela, Hamilton ^{[1, 2]}

Affiliation

^[1] Univ Sao Paulo, Inst Chem Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] Ertl Ctr Electrochem & Catalysis, Kwangju 500712 - South Korea

• Document type: Journal article
• Source: Physical Chemistry Chemical Physics; v. 14, n. 23, p. 8294-8298, 2012.
• Web of Science Citations: 31

Abstract

As in the case of most small organic molecules, the electro-oxidation of methanol to CO2 is believed to proceed through a so-called dual pathway mechanism. The direct pathway proceeds via reactive intermediates such as formaldehyde or formic acid, whereas the indirect pathway occurs in parallel, and proceeds via the formation of adsorbed carbon monoxide (COad). Despite the extensive literature on the electro-oxidation of methanol, no study to date distinguished the production of CO2 from direct and indirect pathways. Working under, far-from-equilibrium, oscillatory conditions, we were able to decouple, for the first time, the direct and indirect pathways that lead to CO2 during the oscillatory electro-oxidation of methanol on platinum. The CO2 production was followed by differential electrochemical mass spectrometry and the individual contributions of parallel pathways were identified by a combination of experiments and numerical simulations. We believe that our report opens some perspectives, particularly as a methodology to be used to identify the role played by surface modifiers in the relative weight of both pathways-a key issue to the effective development of catalysts for low temperature fuel cells. (AU)

• FAPESP's process: 08/05156-0 - Electrocatalysis of the ethanol electrooxidation on platinum monolayers deposited on core-shell nanoparticles
• Grantee: Fabio Henrique Barros de Lima
• Support Opportunities: Regular Research Grants
• FAPESP's process: 09/07629-6 - Electrocatalysis IV: fundamental and applied aspects of electrocatalytic processes, bio-electrocatalysis and kinetic instabilities
• Grantee: Edson Antonio Ticianelli
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Thematic Grants
• FAPESP's process: 09/11073-3 - Investigation of the mechanism of ethanol electro-oxidation on metallic nanoparticles.
• Grantee: Daniel Augusto Cantane
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 09/00153-6 - Spatio-temporal self-organization in electrocatalysis
• Grantee: Raphael Nagao de Sousa
• Support Opportunities: Scholarships in Brazil - Doctorate